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Electrician’s NEC Field Calculator

Wire sizing, voltage drop, conduit fill, motor circuits, and NEC code references on the jobsite.

$9.99. Once. Forever. No subscription. No account. Works offline.

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What’s Inside

Free Features

  • Ohm’s Law / Power Calculator — Enter any 2 of: Volts, Amps, Watts, Ohms, kVA, Power Factor. Get all remaining values solved. 1φ and 3φ modes.
  • Wire Size Calculator (NEC 310) — Load, voltage, phase, conductor material, insulation type, ambient temp, conductors in raceway. Outputs minimum wire gauge with ampacity deration and NEC table reference.
  • Voltage Drop Calculator — Wire gauge, distance, load, voltage. Outputs voltage drop in volts and percentage, pass/fail vs NEC 3%/5% standards, minimum wire size to meet threshold, maximum run length.

Full Unlock ($9.99 one-time)

  • Conduit Fill Calculator (NEC Chapter 9) — EMT, IMC, RMC, PVC, ENT, FMC, LFMC by trade size. Mix wire gauges. Outputs fill percentage, pass/fail vs 40%/31%/53% rules, remaining fill area, recommended upsizes. Bundled Annex C tables for all conductor/conduit combos.
  • Motor Branch Circuit Sizing (NEC 430) — Motor HP, voltage, phase, type. Outputs full-load amps, minimum conductor size, overload protection, branch circuit short-circuit protection, NEMA starter size.
  • Service & Equipment Grounding Conductor — Overcurrent protection size to minimum EGC size (copper/aluminum) per NEC Table 250.122 and grounding electrode conductor per NEC Table 250.66.
  • Box Fill Calculator (NEC 314) — Box dimensions or type selection. Conductor counts by gauge, device count, clamp count. Outputs total fill, required volume, pass/fail, recommended box size if over.
  • Conduit Bending Reference — Visual diagrams for 90° stub-ups, back-to-back 90s, offsets, saddles (3-point and 4-point). Offset height and conduit size to mark distances and multipliers used. Includes multiplier table for 10°, 22.5°, 30°, 45°, 60°.
  • Wiring Diagram Reference — Bundled offline SVG diagrams: single-pole switch, 3-way, 4-way, GFCI with downstream protection, AFCI breaker wiring, split-receptacle, 240V appliance circuits (dryer, range, A/C).
  • NEC Quick Reference — Wire color codes (120/208/240/277/480V systems), standard breaker sizes, NEMA receptacle configurations, Annex C quick-look raceway fill, common terminal torque specs.
  • Accelerometer Wire Pull Angle & Level Meter — Hold phone against conduit. Read slope and angle live. Tap Lock to freeze and confirm drainage slope, conduit plumb, or wall angle for offset calc inputs. Digital bubble level for horizontal/vertical verification. Works offline in dark panels and crawlspaces.
  • Voice Input — “Twenty amp circuit,” “two hundred forty volts three phase,” “one inch EMT,” “number twelve THHN,” “fifty feet,” “copper” — hands-free entry while pulling wire or in tight spaces.
  • Save & History — Save calculation snapshots with project/job labels. On-device PDF export with inputs, outputs, and diagrams. No cloud.
  • NEC 2023 + NEC 2026 Bundled — Both editions included in one app. Switch between editions anytime.

Why We Built This

ElectriCalc Pro, the gold standard with 307 reviews and 4.9 stars, just moved to $29.99/year subscription. Licensed electricians universally hate subscriptions. One documented complaint: “Electricians do not want subscription tools.”

The second-place app, Electrical Calc Elite, costs $19.99 upfront — but NEC 2023 tables are a paid add-on on top of that. Dated 2015 UI, no dark mode, only 124 reviews.

FieldLab’s answer: $9.99 once. NEC 2023 and NEC 2026 bundled. Native SwiftUI dark mode (critical for electricians working in dark panels, crawlspaces, attics). Accelerometer level meter (no competitor offers this). Voice input for hands-free entry in tight spaces. Works 100% offline with zero account.

Built for the Jobsite

  • Dark Mode First — Electrical panels are dark. This isn’t aesthetics — it’s a safety feature. Default to dark mode with full light mode support. High-contrast level indicator readable in pitch-black crawlspaces.
  • Glove-Friendly — 48pt minimum tap targets. Voice input for hands-free entry while pulling wire or on ladders.
  • Works Offline — Zero internet required. No account. No login. Your data never leaves your phone. NEC tables are bundled and always available.
  • Code Citations — Every result shows the NEC table/section reference (e.g., “Per NEC Table 310.16”). Cite code directly to inspectors and contractors.

The Competition Moved to Subscriptions. We Won’t.

ElectriCalc Pro now costs $29.99/year subscription. Electrical Calc Elite costs $19.99 upfront (plus extra for updated NEC tables).

Electrician’s NEC Field Calculator costs $9.99. Once. Both NEC 2023 and NEC 2026 included. That’s it.

We will never charge a subscription. Read why →

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